Influence of fat thickness and femur location on nerve activity computation during electrical stimulation

Cylindrically and anatomically based electrophysiological models have been used to study how different stimulation parameters influence electrical stimulation for muscle activation. The former are less computationally expensive because of their symmetrical properties and simpler geometry. However, the availability of employing simplified models instead of anatomically based models in the prediction of nerve activity has not been investigated. In this study, we compared an anatomically based model of the thigh with its corresponding cylindrically based model to study the difference in nerve activation with respect to stimulation site, the role of fat thickness, bone location, and the presence of the sciatic nerve and blood vessels. As a result, it is clear that the location of the femur and the non-uniformity of fat thickness through different stimulation sites make it difficult to use a cylindrically based model to predict nerve activation in the same way as with the anatomically based model. Nevertheless, the geometry of the cylindrically based model gives a general insight of the nerve activation and could be optimized to match the anatomically based model.